The field of the invention is electrostatic discharge (ESD) protection, and the provision of ESD protection to miniature connectors and connection devices. More particularly, the invention relates to discrete miniature connection devices for protection against ESD associated with human and structural discharges to electrical circuits (hereafter collectively referred to as ESD).
Connectors and printed circuit (PC) boards have found increasing application in electrical and electronic equipment of all kinds. The electrical circuits formed within connectors or on printed circuit boards, like larger scale, conventional electrical circuits, need protection against electrical overvoltage. This protection is typically provided by commonly known ESD devices that are physically secured to the PC board.
Examples of such devices include silicon diodes and metal oxide varistor (MOV) devices. However, there are several problems with these devices. First, there are numerous aging problems associated with these types of devices, as is well known. Second, these types of devices can experience catastrophic failures, also as is well known. Third, these types of devices may burn or fail during a short mode situation. Numerous other disadvantages come to mind when using these devices during the manufacture of a PC board.
It has been found in the past that certain types of materials can provide protection against fast transient overvoltage pulses within electronic circuitry. These materials at least include those types of materials found in U.S. Pat. Nos. 4,097,834, 4,726,991, 4,977,357, and 5,262,754. However, the time and costs associated with incorporating and effectively using these materials in microelectronic circuitry is and has been significant. In addition, these devices tend to have an ESD protection device located far away from possible points of origin of the ESD event, thus allowing for propagation of an overstress or an arc for a considerable distance before the overstress can be shunted to ground. It would be desirable to place the overstress material and shunt near a point of origin of the stress.
While this would be desirable, placing a relief and a shunt is difficult because of the ever-decreasing physical scale and ever-smaller dimensions of electrical devices. Present day designs must incorporate the highest amount of performance possible into the very smallest space available. This leaves little room for even such an important feature as ESD protection. It would be desirable if the ESD protection could be added without changing the design of the electrical device that is being protected. That is, it would be desirable if the ESD protection could be added in an almost modular fashion, with very little or no change to the electrical device which is being protected. The present invention is provided to alleviate and solve these and other problems.